B12 Injections vs. Oral Supplements: Which Is Better? B12 Injections vs. Oral Supplements: Which Is Better? Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta analysis Irish Journal of Medical Science (1971 ) B12 Injections vs Pills Baltimore: Which Works? B12 Shots for Energy: Do They Work, Who Needs Them & What to Expect Greenwich Medical Spa